makeTouchBar()

ViewController.swift

class ViewController: NSViewController {
    // ...
    override func makeTouchBar() -> NSTouchBar? {
        let touchBar = NSTouchBar()
        touchBar.delegate = self
        touchBar.customizationIdentifier = .counterTouchBar
        touchBar.defaultItemIdentifiers = [.increase, .counter, .decrease]
        return touchBar
    }    
}